ENDOBRONCHIAL BRACHYTHERAPY

Dr.Tinku Joseph DM ResidentAIMS, Kochi

Lecture given at Hospital Serdang, Malaysia

Contents

Overview Technique Types Indications Complications

Endobronchial Brachytherapy (EBBT)

Placement of a radioactive source within or in close proximity to a malignancy in order to provide high doses of radiation in close proximity to the tumor.

Palliative therapy Recently-: need for this technique has declined.

Goal-: Reduction in tumor size so that airway symptoms can

be relieved. Compared with (EBRT), EBBT - local radiation is

provided to the lesion (spares other tissues).

Technique

1. Selection of patients2. Planning phase3. FOB/Rigid with or without MV

support4. Placement of Radioactive source

(Ir-192)5. Fluroscopy6. HDR/LDR given

Technique

Technique (step 1)

Technique (step 2)

Technique (step 3)

Technique (step 4)

1

2

Radiation Type

Dose rate of brachytherapy depends upon the energy and rate of decay of the radionuclide used.

Commonly used-: Iridium192

• According to dose rate 1) High dose rate (HDR)- - >12 Gy/Hr

2) Medium dose rate (MDR) - 2-12 Gy/Hr 3)Low dose rate (LDR) - - 0.4 -2 Gy/Hr 4)Ultra low dose rate (ULDR)- -0.01-0.3 Gy/Hr

ISOTOPES USED IN BRACHYTHERAPY can be embedded in

Surface Applicator- placed directly on surface of tumor eg. Hard palate, skin, ocular

Intracavitory- inserted into specially designed apparatus that is placed into body cavity eg. Gynec.malign, nasopharynx

Intraluminal- Various organs with lumen (Oesophagus, endobronchial, biliary etc.)

Interstitial- Directly through tissues encompassing tumor Intravascular- coronaries, peripheral art. internal mammary etc.

10 to 12 Gray (Gy)/hour, Total dose - ranging from 5 to 40 Gy, Dose per session (fraction) varying from 3 to 10 Gy. Treated every 1-2 weeks (takes few mins)HDR/LDR: Treatment times are shorter outpatient procedure. Increase procedure efficiency, Reduce treatment cost. Simpler and safer therapy.

Radiation Type- HDR

Radiation Type- LDR

Delivers less than 2 Gy/hour Total dose of 1500 to 5000 Gy, Given over a few days (usually up to three days)Disadvantages: Manual manipulation of the radionuclide 30 to 70 hours of continuous treatment, Cumbersome radiation protection measures Catheter has to be left in place for the few days of

administration.

Inpatient procedure Catheter displacement More costly than HDR EBBT Largely fallen out of favor.

Radiation Type- LDR

Indications

1. palliative treatment of large obstructing central airway tumors (NSCLC).

2. Metastatic airway tumors.3. Early NSCLC that is limited to the

airway.4. Benign tracheal stenosis

Palliation of central obstructing airway tumors

Palliation of obstructive symptoms caused by large central airway tumors that are not amenable to surgical resection and/orEBRT.

Patients cannot tolerate or fail other local ablative therapies (Nd:YAG laser, APC, or cryotherapy).

Types of cancer that are responsive to EBBT Biopsy proven NSCLC Early NSCLC localized to the airway. Positive resection margins or a stump Recurrence following surgery. Extrathoracic malignancy metastatic to lung

Small cell carcinoma/carcinoid (no response)

Palliation of central obstructing airway tumors

EBBT - patient or tumor criteria

Acute life threatening symptoms of airway obstruction First-: local ablative therapies or EBRT Followed by EBBT

• Efficacy: Subjective and objective improvement following

EBBT (20 to 100 % of patients). No survival benefit associated with EBBT or EBBT in

combination with chemotherapy. EBBT + Coventional methods (beneficial)

Palliation of central obstructing airway tumors

Hemoptysis improve most readily (90% response rate)

Cough and dyspnea may improve less reliably, (underlying conditions such as COPD or radiation fibrosis).

Responses in tumor size and the degree of airway obstruction are most commonly evaluated by chest radiography and bronchoscopy.

70 % of patients have greater than 50% improvement in patency that persists for at least six months.

Palliation of central obstructing airway tumors

Benign airway stenosis

Recurrent tracheal stenosis Following repeated attempts at dilation and stenting,

HDR EBBT (eg, a single 3 to 10Gray [Gy] dose of Iridium192) is beneficial.

Prevents formation of granulation tissue and reduce the recurrence rate of restenosis.

Role in post TB stenosis ???

Contraindications- Absolute

1) presence of fistulas between bronchi and other structures.

(EBBT increases the risk of viscus rupture and fatal hemorrhage)

2) Presence of high grade airway obstruction. Try other modalities first use of brachytherapy will not immediately

shrink tumor size (maximal effect is after three weeks) may result in postradiation tissue edema

and complete airway obstruction.

Moribund patients. Other absolute

contraindications to bronchoscopy in general.

Contraindications- Absolute

1. Lesions in close proximity to large vessels

2. Malignant involvement of the major arteries

3. Significant destruction of the bronchial wall

4. Mediastinal invasion

Contraindications- Relative

High risk of fistula formation and fatal hemorrhage

Complications <5%. Range (5-40%) Early (hours to days) or late (days to

weeks).Early: Infrequent Usually due to bronchoscopy or

catheter insertion. Hemoptysis Catheter displacement Early complications of

bronchoscopy

Late: Radiation bronchitis Airway stenosis. Massive hemoptysis Fistula formation

Complications

Conclusions (EBBT)

Placement of a radioactive source within or in close proximity to a malignancy in order to provide high doses of radiation close to the tumor.

EBBT is a good palliative treatment for endoluminal neoplasms of the lungs, either alone or in combination with other procedures.

Used in benign airway stenosis. HDR/LDR EBBT Bronchoscopy guided procedure. Combined with EBRT/APC/Nd YAG

(better results) Good tolerance and low

complication rate.

Conclusions